Matrix multiplication using multiple locales - chapel

Question

Hi I wanted to see if anyone can see any glaring problems with my code. I am trying to run my code over two Nvidia Jetson boards to utilize 8 cores for speed up. I want to compare the speed of using one board compared to two boards. I have the Chapel environment set up to be allowed for multiple locale execution.
Here is my implementation:
use LinearAlgebra, Norm, Random, Time;
var t : Timer;
writeln("Size of your matrix?");
var size = read(int);
var grid : [1..size, 1..size] uint(8);
var grid2 : [1..size, 1..size] uint(8);
var grid3 : [1..size, 1..size] int;
fillRandom(grid);
fillRandom(grid2);
t.start();
forall loc in Locales do
on loc do
forall i in 1..size do
forall j in 1..size do
forall k in 1..size do
grid3[i,j] += grid[i,k] * grid2[k,j];
t.stop();
writeln("Done!:");
writeln(t.elapsed(),"seconds");
t.clear();
I keep getting:
error: Only 1 locale may be used for CHPL_COMM layer 'none'
To use multiple locales, see $CHPL_HOME/doc/rst/usingchapel/multilocale.rst
When I run the cores.chpl file which has:
coforall loc in Locales do
on loc do
writeln("locale ", here.id, " named ", here.name, " has ", here.numPUs(), " cores.");
This is the output:
locale 0 named JetsonNano has 4 cores.
locale 1 named JetsonNano2 has 4 cores.
So I know the environment is set up right.
I'm just not sure if I am setting my matrix multiplication code right for it be allowed over multiple locales.

Answer 1

The message:
error: Only 1 locale may be used for CHPL_COMM layer 'none'
To use multiple locales, see $CHPL_HOME/doc/rst/usingchapel/multilocale.rst
indicates that when you compiled your Chapel program, you either had CHPL_COMM unset, or set to none in the session where the compilation took place. Try setting CHPL_COMM=gasnet in your current session (or, equivalently, compiling with --comm=gasnet), recompiling, and then running with -nl 2.
Within a given session, you can run $CHPL_HOME/util/printchplenv to see what the current set and/or inferred environment variables are. For a given Chapel program you can run ./myChapelProgram --about to get information about the settings at the time it was compiled.
If you plan to work with CHPL_COMM=gasnet most of the time, you can use a Chapel configuration files to avoid re-setting things over and over again.